The Mechanisms Underlying In AMPK Regulation Of Exercise Endurance In Mice

Objective:AMPK is an important energy sensor in skeletal muscles. AMPK expression and its activation level are closely related to training and exercise endurance, but so far, the mechanisms underlying in AMPK regulation of exercise endurance is unclear. This study focuses on the phosphorylation of AMPK and its effect on exercise capacity of skeletal muscle and its mechanism.Methods and Subjects:We subjected wild-type C57BL/6mice to treadmill exercise until exhaustion, detected the dynamic expressions of AMPK and its phosphorylation level by using Western blot. Moreover, we detected the expression of AMPK downstream target gene, PGC-lα, and fiber type-specific genes expression by using real time PCR method to explore the molecular mechanisms underlying in the effect of AMPK on exercise capacity.Results:1) There were no significant difference in the expression of AMPK a, β2in slow-twitch soleus muscles, fast-twitch plantaris muscles and mixed gastrocnemius muscles; and the expression of p-AMPK a, AMPK p1and p-AMPK β108consisted with Troponin I-SS expression and showed a significant high expression in slow-twitch soleus muscles;2) AMPK a expression showed little change in skeletal muscles during exercise, p-AMPK a expression continued to increase in the gastrocnemius muscles during exercise, but increased first and decreased slightly in the soleus and plantaris muscles during exercise;3) AMPK p1/2expression showed little change in skeletal muscles during exercise, the expression of p-AMPK β108is consistent with that of p-AMPK a, which continued to increase in the gastrocnemius muscles during exercise, but increased first and decreased slightly in the soleus and plantaris muscles during exercise;4) real time PCR results showed that the expression of PGC-1α mRNA continued to increase in skeletal muscle during exercis, and slow muscle fiber gene (MHC-Ⅰ, MHC-Ⅱα) and increased at first then decreased as a whole, while the fast-twitch fiber-related genes (MHC-Ⅱb) showed an increasing trend after the first drop.Conclusions:Therefore, in this study, we further validated the importance of the AMPK expression and phosphorylation in skeletal muscle for exercise endurance, made a preliminary study of molecular mechanisms in AMPK regulation of exercise endurance, which has important theoretical value in guiding the athletes for targeted training to improve the effect of exercise.